LED pattern projector for 3D camera platforms

Abstract

A light pattern projector with a pattern mask to spatially modulate an intensity of a wideband illumination source, such as an LED, and a projector lens to reimage the spatially modulated emission onto regions of a scene that is to be captured with an image sensor. The projector lens may comprise a microlens array (MLA) including a first lenslet to reimage the spatially modulated emission onto a first portion of a scene, and a second lenslet to reimage the spatially modulated emission onto a first portion of a scene. The MLA may have a fly's eye architecture with convex curvature over a diameter of the projector lens in addition to the lenslet curvature. The pattern mask may be an amplitude mask comprising a mask pattern of high and low amplitude transmittance regions. In the alternative, the pattern mask may be a phase mask, such as a refractive or diffractive mask.

What is claimed is: 
     
       1. A camera platform, comprising:
 an image sensor array to collect light from a scene within a field of view of the image sensor array; and 
 a light projector to cast a light pattern upon the scene, wherein the light projector further comprises:
 a light source; 
 a mask to spatially modulate an intensity of emissions from the light source; and 
 a microlens array (MLA) to project a same spatially modulated emission onto multiple portions of the scene. 
 
 
     
     
       2. The camera platform of  claim 1 , wherein the MLA comprises a first lenslet to reimage the spatially modulated emission onto a first portion of the scene, and a second lenslet to reimage the spatially modulated emission onto a second portion of the scene. 
     
     
       3. The camera platform of  claim 2 , wherein:
 the light source comprises a first light emitter; 
 the image sensor array comprises a first sensor pixel line is to integrate photocharge for a first portion of the scene over a first time increment; 
 the image sensor array comprises a second sensor pixel line is to integrate photocharge for a second portion of the scene over a second time increment; and 
 the light projector is to illuminate the first portion and the second portion of the scene with illumination from the first light emitter during the first and second time increments. 
 
     
     
       4. The camera platform of  claim 1 , wherein the mask is between the light source and the MLA. 
     
     
       5. The camera platform of  claim 4 , wherein the mask is in contact with a surface of the projector lens proximal to the light source. 
     
     
       6. The camera platform of  claim 1 , wherein the MLA comprises a plurality of lenslets, each having a convex surface distal from the light source. 
     
     
       7. The camera platform of  claim 1 , wherein the mask comprises at least 400 features and wherein the MLA comprises at least 9 lenslets. 
     
     
       8. The camera platform of  claim 1 , wherein the mask is an amplitude mask comprising a mask pattern of high and low amplitude transmittance regions. 
     
     
       9. The camera platform of  claim 1 , wherein the mask is in contact with a substantially planar lens surface, wherein the MLA comprise a first material, and wherein the low transmittance regions comprise a second material of a different composition than the first material. 
     
     
       10. The camera platform of  claim 1 , wherein the mask and the projector lens comprise a monolithic optical element of substantially homogeneous composition. 
     
     
       11. A pattern projector to cast a light pattern upon portions of a scene, wherein the pattern projector further comprises:
 an amplitude mask comprising a mask pattern of high and low transmittance regions to spatially modulate an intensity of an emission from an illumination source; and 
 a projector lens, wherein the projector lens comprises a microlens array (MLA), wherein the amplitude mask is proximal a first projector lens surface, and wherein a first lenslet and second lenslet of the MLA each has a convex projection surface distal from the mask. 
 
     
     
       12. The pattern projector of  claim 11 , wherein the first lenslet is to reimage a spatially modulated emission onto a first portion of a scene, and the second lenslet to reimage the spatially modulated emission onto a second portion of the scene. 
     
     
       13. The pattern projector of  claim 11 , wherein the mask pattern comprises at least 400 features and wherein the MLA comprises at least 9 lenslets. 
     
     
       14. The pattern projector of  claim 11 , wherein the amplitude mask is in contact with the first projector lens surface. 
     
     
       15. The pattern projector of  claim 11 , wherein the projector lens has a fly's eye architecture in which a lens projection surface has convex surface curvature over a diameter of the projector lens. 
     
     
       16. The pattern projector of  claim 15 , wherein the first projector lens surface has concave surface curvature over the diameter of the projector lens. 
     
     
       17. The pattern projector of  claim 15 , wherein the first projector lens surface is substantially planar. 
     
     
       18. The pattern projector of  claim 17 , wherein an area of the mask is smaller than an area of the lens projection surface. 
     
     
       19. The pattern projector of  claim 11 , further comprising an LED light source. 
     
     
       20. A mobile computing platform, comprising:
 a battery; 
 a microprocessor coupled to the battery; 
 an image sensor array coupled to the microprocessor, the image sensor array to collect light from a scene within a field of view of the image sensor array; and 
 the pattern projector of  claim 11 .